Fabrication and field emission performance of arrays of vacuum microdiodes containing CuO nanowire emitters grown directly on glass without a catalyst

Abstract

Arrays of vacuum microelectronic sources are fabricated on a glass substrate using cupric oxide (CuO) nanowire emitters. The arrays of electron sources possess a microdiode structure, which can effectively induce field emission and control the delivery of emitted electrons to the anode in a triode-type device operation. A technique for precisely growing CuO nanowires at the centre of microcavities in an array without using a catalyst and at temperatures as low as 400°C is presented. Such a simplified fabrication procedure results in improved field emission performance from the array compared with previous vacuum microelectronic devices. Typical prototype devices have turn-on gate voltages as low as 169 V to give emission current densities of 10 μA/cm2 at the anode. The ratio of anode current to cathode current reaches ∼0.85, and the maximum change in emission current density per volt is 1 μA/cm2. Electron emission from the arrays is stable and reproducible under either pulsed or direct current fields. These characteristics indicate that microgate-controlled CuO nanowire emitters may find application in practical devices.